The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

Alleged father-son shooter denied bail

A man accused of trying to kill his sister's on-off boyfriend and the man's father on an inner Sydney street has failed in his bail release bid.

Corey George Farrell, 28, allegedly shot father and son Michael and Joshua Smart outside their Pyrmont home last April.

During a bail application in the NSW Supreme Court on Thursday, Farrell's barrister James Trevallion said the alleged shooting was sparked by intense animosity between Farrell and 24-year-old Joshua Smart, who had been going out with Farrell's sister Monique Farrell.

Smart is said to have sent Monique a slew of threatening text messages in the lead-up to the attack.

One message read to the court on Thursday said: "See you soon slut, I hope your brother is there ... I will shot the f*** out of him".

Smart allegedly sent his girlfriend another text following the shooting, which read: "Ur bro just shot me and my dad".

But Mr Trevallion said the latter text was "doomed to be struck out" as evidence in Farrell's trial, which is set to take place next July.